As a bonding pad of a semiconductor device, a bonding pad constituted of a metal including aluminum has been known. When a wire is bonded to the bonding pad, the bonding pad is deformed by stress applied to the bonding pad at the bonding. Consequently, the metal that constitutes the bonding pad is ejected from a bonded portion with the wire to an outside of the bonded portion. This phenomenon is called an aluminum splash. When the aluminum splash reaches a vicinity of another bonding pad, an insulating distance between the bonding pads is shortened, and there may be a risk of a short circuit.
Japanese Patent Application Publication No. 2012-109419 discloses a bonding pad that includes a protrusion on its surface. The protrusion is disposed around a region to which a wire is to be bonded. The protrusion is provided along a peripheral edge of the bonding pad. When a wire is bonded to the bonding pad, the protrusion suppresses the aluminum splash from spreading to an outside of the bonding pad. Therefore, a short circuit between the aluminum splash and another bonding pad is suppressed.